Rattlegram vs DnDD
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Rattlegram
This app utilizes advanced COFDM technology for audio-based SMS transmission. It supports various modes with specific encoding and modulation techniques, requiring minimal bandwidth for efficient data transfer.
- COFDM technology
- Audio-based SMS
- 160 ms OFDM symbols
- Differential PSK modulation
- Forward error correction
- Low bandwidth requirement
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COFDMTV is based on COFDM (coded orthogonal frequency-division multiplexing) technology: - 160 ms long OFDM symbols - 6.25 Hz per sub-carrier - 1/8 guard interval - differentially encoded PSK (phase-shift keying) modulation - systematic polar codes for forward error correction Currently Modes 14, 15 and 16 are supported: Using either SPC(2048, 1392), SPC(2048, 1056) or SPC(2048, 712) with CRC32C aided SCL decoding and differential QPSK modulation for the payload. Only a bandwidth of 1600 Hz is needed and the transmission of either 85, 128 or 170 bytes take about one second with the leading noise and fancy header disabled.
DnDD
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DnDD is a bulletin board system. But it tries to overcome one-off argument of internet bulletin boards. Posts in DnDD are like pages in a book so that people can easily talk about one subject continuously. DnDD also have voting system. A post can be connected to another post via comments. Anybody can make their own group and use DnDD as a bulletin board and voting platform.
Screenshots
Verdict
The clearest difference is iOS requirement: DnDD at 13.4 against Rattlegram's 17.6. On price, update cadence, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Rattlegram ships an update every 9 months, DnDD every 10 months. The most recent releases landed on September 25, 2026 and September 17, 2026 respectively.
| Parameter | Rattlegram | DnDD |
|---|---|---|
| Price | Free | Free |
| Rating | 4.5 (23 ratings) — better | — |
| Positive reviews | 90.0% of reviews | — |
| Number of ratings | 23 — better | — |
| Update frequency | Every 9 months — better | Every 10 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.6 | 13.4 — better |
| Further details — not scored | ||
| Size | 1 MB | 20 MB |
| Age rating | 4+ | 4+ |
| Developer | aicodix GmbH | ZetaSoft Co.ltd. |
In-app purchases
Rattlegram
No in-app purchases
DnDD
No in-app purchases
